• 한국산학기술학회논문지
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• 제10권7호
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• pp.1549-1555
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• 2009

무선센서 네트워크에서 노드들의 데이터를 수집하고 기지국에 전달하는 중계노드의 위치(Relay Node Placement)를 구하는 문제는 전체 네트워크의 생존시간에 관련되어 있기 때문에 매우 중요하다. 중계노드 위치문제는 전체 네트워크의 센서노드에서 소비되는 에너지를 최소화시키는데 그 초점이 맞추어져 있다. 그러나 중계노드 위치와 센서노드와의 거리가 모두 다르므로 센서노드에서 소비되는 에너지의 불균형이 초래된다. 본 논문에서는 클러스터링 모델에서 에너지 균형비(Energy Balance Ratio)라는 개념을 제안하고 이 에너지 균형비를 최대화시키는 목적함수를 사용하여 중계노드의 위치를 구한다. 에너지 균형비를 최대화시키는 것은 클러스터에 할당된 센서노드들의 에너지 소비를 클러스터 간에 균형 잡히게 한다. 이것은 궁극적으로 대규모 센서 네트워크의 에너지 소비를 최소화시켜서 네트워크 생존기간을 최대화시키는 효과가 있다. 그러나 이 문제의 해를 구하는 것은 NP-hard 문제이므로 완전해(Exact Solution) 를 구하는 것은 현실적으로 힘들다. 따라서 제약프로그래밍 방법을 사용하여 에너지 균형비와 중계노드 위치를 함께 고려하는 EBR-RNP 문제로 모델링하여 근사해를 구한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.947-952
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• 2001

The prediction model is proposed to estimate the variation of compressive strength of fly ash concrete with aging. After analyzing the experimental result with the model, the regression results are presented according to fly ash replacement content and water/cement ratio. Based on the regression results, the influence of fly ash replacement content and water/cement ratio on apparent activation energy was investigated. According to the analysis, the model provides a good estimate of compressive strength development of fly ash concrete with aging. As the fly ash replacement content increases, the limiting relative compressive strength and initial apparent activation energy become greater. The concrete with water/cement ratio smaller than 0.40 shows that the limiting relative compressive strength and apparent activation energy are nearly constant according to water/cement ratio. But, the concrete with water/cement ratio greater than 0.40 has the increasing limiting relative compressive strength and apparent activation energy with increasing water/cement ratio.

• 한국소음진동공학회논문집
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• 제20권3호
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• pp.296-307
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• 2010

This paper deals with the energy transmission ratio of the elastic waves transmitting through a solid wall. Based on the displacement of the reflected and transmitted waves relative to the incident waves, the energy transmission ratio of the wave was obtained by multiplying the vibration velocity and stresses. Numerical calculation provided with the transmission ratio and refraction angle corresponding to the incidence angle, and it showed the mode conversion from the incident longitudinal wave to the transmitted transverse wave in particular incidence angle range. The paper established a procedure to find the incidence angle of the maximum energy transmission ratio and confirmed it by experiment.

• 한국지반공학회지:지반
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• 제12권5호
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• pp.117-126
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• 1996

표준관입시험은 시험절차의 간편성 등 많은 장점에도 불구하고 시험장비와 시험보조장치 및 시험관리 등에 따라 시험결과인 N치에는 여러가지 오차가 포함되는 시험으로 알려져 있다. 특히, 해머가 낙하할 때에 발생하는 에너지 손실 때문에 실제의 해머 타격에너지와 이론치는 크게 다르기 마련이다. 이 연구에서는 초음파 송수신장치와 PC를 이용하여 국내의 여러 현장에서 시행되고 있는 표준관입시험에서 해머타격에너지를 측정하여 이론치와 비교하였다. 연구결과 R-P해머와 자동해머의 해머에너지비는 이론치에 대하여 각각 64.2%및 75.0%로 측 정되었다. 측정결과에 동적효율 0.72를 적용하여 측정 N치를 보정할 수 있는 평균에너지비를 산출한 결과는 각각 46% 및 54%였다.

• 한국지반공학회지:지반
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• 제13권1호
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• pp.169-182
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• 1997

표준관입시험에서 해머가 낙하하여 발생한 충격에너지가 샘플러에 전달되는 과정에 여러 가지 제한 및 문제점 때문에 에너지 손실이 일어나게 마련이다. 시험결관인 N치를 보정하기 위해서는 로드에 전달되는 에너지 수준이 측정되어야 한다. 이 연구에서는 충격에너지와 모루를 통하영 로드에 전달되면서 손실된 에너지가 반영된 로드 에너지의 비율 즉, 표준관입시험의 동적 효울을 Charpy 충격시험장치를 이용하여 측정하고, 항타 분석 프로그램인 GRL-WEAP해석과 현장시험으로 비교 및 확인 하였다. 연구결과 R-P해머와 바동해머의 동적표효율이 0.726과 0.728로 각각 산정되었으나 0.72로 같게 제시하였다. 이 값에 현장측정한 해머에너지 수준 64.2%(R-P)및 75.%(자동)를 적용하여 측정 N 가치를 보정할 수 있는 SPT의 평균에너지비를 46.7% 및 54.5%호 산정하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.513-516
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• 2004

The purpose of this study is to investigate properties of porous concrete according to volume of binder and compaction energy. The result of this study, as compaction energy goes on increasing, the actual measured void ratio is decreased according as a change of compaction energy and volume of binder. The compaction energy has a very near value by target void ratio on the whole when it is $50kN{\cdot}m/m^2,\;50\~75kN{\cdot}m/m^2$ in case of target void ratio is $15\%\;and\;25\%$. As compaction energy goes on increasing, compressive strength of specimens picked up when target void ratio is $20\%\;and\;25\%$. Also, compressive strength of specimens bluntly picked up when compaction energy is over $50\~75kN{\cdot}m/m^2$.

• 한국지열·수열에너지학회논문집
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• 제9권1호
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• pp.15-19
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• 2013

In this Study, effect of core position, area ratio and orientation of building on energy load is examined using TRNSYS17. This parameters are major parameters of the conceptual design stage. Reference model is square floor plan($1,444m^2$), centered core and 29% core area ratio. As the results, without considering the building orientation, the annual heating load of central building with 1:1 area ratio is lowest ($10.33kWh/m^2yr$) and the annual cooling load of off-central building with 1:1 area ratio is lowest ($59.27kWh/m^2yr$). As area ratio is bigger, cooling load is lower and heating load is higher. But if we consider building orientation, orders of heating load and cooling load are changed for area ratio and orientation.

• Preventive Nutrition and Food Science
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• 제1권2호
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• pp.239-243
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• 1996

Three hundred and twenty-four 1 day old chicks were used to determine the effects of fat source and energy to protein ratio on growth performance , carcass composition and the efficiency on nutrient utilization. Chicks were assigned. in a completely randomized design, to 3*3 factorial arrangement of treatments. Chicks received one of three fat sources (n0 fat, tallow, corn oil) and one of three energy to protein ratios(16, 14 and 12kcal ME/g CP). All diets were formulated to be isocaloric(3.2Mcal ME/kg diets) using published ME values for the diet ingredients. Addition of tat to the diet increased ADG, average daily feed intake, and gain to feed, Chicks fed diets containing fat had increased percentage body DM and ether extract(EE), but percentage CP was not different, Chicks fed diets containing fat had increased efficiency of protein and energy deposition. Addition of fat ad either fallow or corn oil yielded similar results. Reducing the energy to protein ratio of the diet did not affect ADG or gain to feed, but tended to decrease average daily feed intake(p=0.80), as well as resulting in linear(p<0.05) reductions in body percentage DM., EE and also total EE. Increasing the energy to protein ratio did not affect percentage or total body Cp. Adding fat to poultry diets improved growth performance and the efficiency of growth chicks. Decreasing the energy to protein ratio did not affect growth performance, but reduced EE in the body of Chicks.

• KIEAE Journal
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• 제15권1호
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• pp.21-27
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• 2015

In the case of public buildings, fast communication and transparency in the administration and the public, as well as ensuring visibility and lighting performance using a glass curtain wall is symbolically expressed through the transparent glass skin. This study is a simulation in order to derive the basic data for the establishment of the improvement of the heating and cooling load analysis according to the window area ratio changes with respect to the high effectiveness of the government's large public building energy consumption analysis and green building certification system of guidelines was analyzed by a change in the energy load. Glass curtain wall is light and visibility, the symbolic meaning of communication, etc., but is widely used in a variety of characteristics, in terms of energy consumption being disadvantaged sheath plan should have been. Design, including the Atrium, is much less energy than energy consumption by the window area ratio. Thus, while compliance with design guide lines, the atrium and I like the burden of a large space ratio and energy load consists of only glass suggest that require more research on that given in the guidelines.

• 오토저널
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• 제10권2호
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• pp.46-53
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• 1988

Effect of Notch Shape and Hardness Ratio on Characteristics of Impact Fracture in Dual Phase Steels. In this study, it is investigated the effect of notch shape and hardness ratio on the characteristics of impact fracture in dual phase steels. The impact test was carried out at the temperature range from -40.deg. C to room temperature with Instrumented Charpy Impact Tester. The main results obtained are as follows; 1, The maximum impact bending strength (.sigma.$_{max}$) increases with the tensile strength. Also, the impact energy depends on .sigma.$_{max}$. 2, In room temperature, the impact energy depends on crack-initiation energy (E$_{i}$) in case of the high hardness ratio (R=3.4), whereas depends on crack-propagation energy (E$_{p}$) in case of the low hardness ratio (R=1.8) and the dependence of crack-initiation energy of the impact characteristics decreases with increasing test temperature. These phenomena are result from the difficulty of cleavage facet formation.ion.ion.